Cord-reinforced cellulose sponge material



United States Patent O CORD-REINFORCED CELLULOSE SPONGE MATERIAL Thurlow G. Gregory, Cleveland Heights, Ohio N Drawing. Application May 5, 1958 Serial No. 732,787

4 Claims. or. 106164) This is a continuation-in-part of my application Serial No. 658,228, filed May 10, 1957, now abandoned, for Cellulose Sponge Material.

This invention relates to an improvement in the wearing properties of these sponges by means of reinforcing cords randomly positioned therein.

In the manufacture of cellulose sponge a pasty material is prepared by mixing together fibers such for example as jute fibers, viscose and sodium sulfate decahydrate or other comparable pore-forming substance. This mixture is thereafter placed into molds and the viscose content is coagulated by appropriate means such as the application of heat and/or the chemical action of a suitable solution. tent the crystalline pore-forming substance is melted and drained from the mass and the resulting spongelike material is washed, dried and cut into blocks of appropriate sizes and shapes. Such sponges are now in Wide current use for toilet sponges and for simple household cleaning purposes. However when these sponges are subjected to hard usages in industry and some of the more strenuous household scrubbing operations the small single fibers of the sponge break and the sponge splits apart at numerous places. By means of this invention great additional strength and wearability of such sponges is achieved. This additional strength is over and beyond that achieved by cellulose sponges of comparable density disclosed by prior inventors. Such sponge material is designated herein and in the claims as cellulose sponge.

I have discovered that when a small ratio of fibrous material of the order of the body material of the sponge is twisted, platted, woven or otherwise formed into soft and pliable cords and these soft and pliable cords are cut into relatively short lengths and these short cords are randomly distributed in the mass and extend randomly in all directions within the final body material that great strength is added to the sponge. I have also discovered that a dual strengthening action or result is achieved. By this I mean that the binder strengthens the cords and it also binds the fibrous body material to these strengthened cords. The reinforcing cords are stronger than the individual fibers of the body material of the sponge and are bonded to the fibers of the body material by the binder of the sponge. They reinforce and strengthen the cellulose sponge in substantially all directions and promote long Wear of the sponge and inhibit tearing of the sponge when the sponge is subjected to hard usage. This is of special consequence and value when the cellulose sponge articles are used as floor mops and for cleaning large and rough machinery parts, cement blocks, tile and the like with water and some other liquid solvents. It is preferred, but not essential, that the reinforcing cords be formed from the same substance as the body of the sponge. This is amplified below.

I have also discovered that when these reinforcing cords are formed from the same kind of fibers as those which form the body material of the sponge or of other equivalent fibers having approximately the same specific gravity and approximately the same degree of wettability that After the coagulation of the viscose conice these cords randomly disperse within the mass. By wettability I means the ability to absorb water after the order of jute and also the property of becoming limp when wetted with water after the order of jute and similar fibers. However, when the terms wet, wetted, wettability and the ability to absorb water are employed herein and in the appended claims they do not necessarily mean that the fibers are wetted with water during the fabrication of the sponge material but these terms are intended to describe the nature of the fibers.

I have also discovered that when the short reinforcing cords are soft and pliable as herein disclosed that they are compatible with the fibrous body material and yield to pressures during fabrication of the sponge mass and furthermore they do not as readily and undesirably orient in one direction as do relatively stifi elements of the same approximate sizes and lengths. Because the cords do not appreciably orient in one direction but extend in substantially all directions and because each cord often is bonded to many different strands of jute and frequently bonds to a single jute or like strand at more than one place these cords reinforce the respective tiny threadlike filaments of the web-like porous body and thereby strengthen the mass as a whole more than would be expected. This added strength is achieved without appreciably increasing the resistance of the sponge to compression or to impact.

I have also discovered that when the short, soft and pliable reinforcing cords employed are of approximately the same specific gravity as that if the body material they tend to retain their respective positions within the mass by which I mean that they do not readily and undesirably sink to the bottom of the mass or to undesirably rise to the top of the mixture during the fabrication of the sponge material.

In the manufacture of cellulose sponges the cellulose content of the viscose and the ratio of the pore-forming crystals and the ratio of the fibrous body material to the total mix are known in the art to vary widely according to the preferences of various producers and the texture of the sponges which they elect to produce in a given lot. By the same token, the proportions of these elements are not critical to this present invention. However, the reinforcing cords herein disclosed should be present in quantity between-approximately 1% and approximately 10% of the weight of the other fibers of the final body material of the completed sponge and these reinforcing cords preferably should be between approximately one one-hundredth of one inch and approximately one sixteenth of one inch in diameter and between approximately three eighths of one inch and approximately two inches in length. Various sizes and various lengths and various kinds of the reinforcing cords may, if and when desired, be present in a given mix. In some instances the reinforcing cords may be as short as approximately one fourth of one inch.

The following are given as preferred specific formulas for making my cord-reinforced cellulose sponge they being given as illustrations and not as limitations.

Thoroughly mix together and make a paste of the the following in parts by weight- Place the above described paste into molds of the desired shape and size. Coagulate the viscose of the mixture while the mixture is still in the molds by immersing the molds and the mixture in a hot aqueous solution of sodium sulfate as is well known in the art. Drain out the dissolved pore-forming matter. Wash and dry the resultant sponge.

Another illustrative formula is:

Jute fibers (body material) 2.80 Soft and pliable jute cords approximately one thirty-second of one inch in diameter and approximately five eighths of one inch in length 0.20 Sodium sulfate decahydrate crystals 80.00 Viscose with cellulose content 17.00

The following is given as the best mode but not the only mode of carrying out the invention: First wet the reinforcing cords with a small portion of the viscose allowing a brief time for the viscose to soak into the respective cords. Next, wet the remainder of the fibrous body material with the remainder of the viscose. Then mix together the wetted cords, the wetted body material and the pore-forming crystals of sodium sulfate decahydrate and thoroughly stir or otherwise mix the total into a paste. Place this paste into molds of the desired shape and size. Coagulate the viscose in the mixture while the mixture is still in the molds by immersing the molds and the mixture in a hot aqueous solution of sodium sulfate as is well known in the art. When so immersed the viscose coagulates and the pore-forming sodium sulfate decahydrate crystals go into solution and may be drained out. Drain, wash and dry the resultant sponge. The sequence of the mixing operations given are desirable but they are not essential. During a thorough mixing of the ingredients into the pasty consistency as above described the sodium sulfate decahydrate crystals serve the additional useful function of physically dispersing the reinforcing cords within the total mixture. The sodium sulfate coagulant is a neutral salt. Many other substances which are equivalent in function for the making of cellulose sponge are known in the art most but not all of which are neutral salts. Neutral salts are preferred as coagulants, sodium sulfate being the most desirable.

By the expression soft and pliable fibers of organic matter and other expressions comparable thereto when employed herein and in the appended claims to denignate the body material of the sponge and to designate the content of the reinforcing cords I mean jute or equivalent organic matter conventionally employed for making cellulose sponge of which said fibrous matter cotton fibers are another example. By such expressions I also mean body material and cords formed from soft and pliable fibrous matter of which jute and cotton are examples as distinguished from fibers or strands of asbestos, rock wool, metallic wire or other equivalent inorganic matter. By such expressions I also mean soft, fibrous organic matter which becomes limp when wetted with water as distinguished, for example, from hard, splinterlike portions of untreated wheat straw which remain stiff when so wetted. While it is not essential that the reinforcing cords be formed from the same specific kind of fibers as the fibers of the body material, it is preferable that they be of the same material because such cords tend to accept dye at the same rate as the like body material and to the same degree as this body material. The employment of the same material for the reinforcing cords avoids splotchiness of color in the final mass when completed and ready for use whether or not the finahmass is dyed. Also, the final sponge is of a more uniform texture. By the terms cords, reinforcing cords, ute cords, cotton cords and the like when employed herein and in the claims I mean cords to reinforce soft, porous, sponge-like masses and to inhibit the tearing of such soft, porous, sponge-like masses and I 4 also mean to distinguish these cords from and thereby to exclude cords which are embedded as filler material within solid masses as a means of increasing the solidity of or the impact strength of the said solid masses.

When the expression binder of coagulated viscose or other expression comparable thereto is employed herein and in the appended claims I mean the binder such as is present in the conventional widely known cellulose sponges now in general use in homes and in industry which said sponges are made by the same or equivalent means as herein described and employing the same or equivalent ingredients as herein described whereby to form the binder of the sponge whether or not that binder is held to be regenerated cellulose.

When the term jute is employed herein and in the appended claims both in reference to the body material and the reinforcing cords I mean the term to embrace jute, cotton and any comparable fiber or mixture of fibers that simple experimentation by one skilled in the art will be shown to be an equivalent of the jute for the purposes of this invention. By the terms sodium sulfate decahydrate and sodium sulfate I mean to include these chemicals and any and all other chemicals which simple experimentation by one skilled in the art will show to be equivalents for the purposes of this invention.

Having described my invention, I claim:

1. A cord-reinforced cellulose sponge article consisting of body material of soft and pliable fibers of jute, a plurality of soft and pliable reinforcing cords randomly distributed and extending in random directions within and substantially throughout the said body material and a binder of regenerated cellulose, the said reinforcing cords being within ranges between approximately one fourth of one inch and approximately two inches in length and approximately one one-hundredth of one inch and approximately one sixteenth of one inch in diameter and being present in quantity within a range between approximately l% and approximately 10% of the weight of the fibers of the body material the said reinforcing cords being formed from soft and pliable fibers of jute.

2. A cord-reinforced cellulose sponge article consisting essentially of body material of soft and pliable cotton fibers, a plurality of soft and pliable reinforcing cords randomly distributed and extending in random directions within and substantially throughout the said body material and a binder of regenerated cellulose, the said reinforcing cords being within ranges between approximately one fourth of one inch and approximately two inches in length and approximately one one-hundredth of one inch and approximately one sixteenth of one inch in diameter and being present in quantity within a range between approximately 1% and approximately 10% of the weight of the fibers of the body material the said reinforcing cords being formed from soft and pliable cotton fibers.

3. A cord-reinforced cellulose sponge composition consisting essentially of body material of soft and pliable jute fibers, a plurality of soft and pliable cords randomly distributed and extending in random directions within the said body material, pore-forming means consisting of granules of sodium sulfate decahydrate crystals randomly distributed within the mass of body material and the soft pliable cords, sodium sulfate in aqueous solution and viscose the said soft and pliable cords being within ranges between approximately one fourth of one inch and approximately two inches in length and approximately one one-hundredth of one inch and approximately one sixteenth of one inch in diameter and being present in quantity within a range between approximately 1% and approximately 10% of the weight of the fibers of the body material the said randomly dispersed cords being formed from soft and pliable jute fibers.

4. A cord-reinforced cellulose sponge composition consisting essentially of body material of soft and pliable cotton fibers, a plurality of soft and pliable cords randomly distributed and extending in random directions within the said body material, pore-forming means consisting of granules of sodium sulfate decahydrate crystals randomly distributed within the mass of body material and soft pliable cords, sodium sulfate in aqueous solution and viscose the said soft and pliable cords being within ranges between approximately one fourth of one inch and approximately two inches in length and approximately one one-hundredth of one inch and approximately one sixteenth of one inch in diameter and being present in quantity within a range between approximately 1% 10 and approximately 10% of the weight of the fibers of the body material the said randomly dispersed cords being formed from soft and pliable cotton fibers.

6 References Cited in the file of this patent UNITED STATES PATENTS 2,295,823 Banigan et a1. Sept. 13, 1942 2,464,772 Drisch Mar. 15, 1949 2,706,159 Kreek et a1. Feb. 13, 1952 2,836,503 Osburn May 27, 1958 OTHER REFERENCES Modern Plastics Encyclopedia, vol. I (1947), pages 192-193. 

3. A CORD-REINFORCED CELLULOSE SPONGE COMPOSITION CONSISTING ESSENTIALLY OF BODY MATERIAL OF SOFT AND PLIABLE JUTE FIBERS, A PLURALITY OF SOFT AND PLIABLE CORDS RANDOMLY DISTRIBUTED AND EXTENDING IN RANDOM DIRECTIONS WITHIN THE SAID BODY MATERIAL, PORE-FORMING MEANS CONSISTING OF GRANULES OF SODIUM SULFATE DECAHYDRATE CRYSTALS RANDOMLY DISTRIBUTED WITHIN THE MASS OF BODY MATERIAL AND THE SOFT PLIABLE CORDS, SODIUM SULFATE IN AQUEOUS SOLUTION AND VISCOSE THE SAID SOFT AND PLIABLE CORDS BEING WITHIN RANGES BETWEEN APPROXIMATELY ONE FOURTH OF ONE INCH AND APPROXIMATELY TWO INCHES IN LENGTH AND APPROXIMATELY ONE ONE-HUNDREDTH OF ONE INCH AND APPROXIMATELY ONE SIXTEENTH OF ONE INCH IN DIAMETER AND BEING PRESENT IN QUANTITY WITHIN A RANGE BETWEEN APPROXIMATELY 1% AND APPROXIMATELY 10% OF THE WEIGHT OF THE FIBERS OF THE BODY MATERIAL THE SAID RANDOMLY DISPERSED CORDS BEING FORMED FROM SOFT AND PLIABLE JUTE FIBERS. 